Greek railway signalling

OSE signalling

History

Old style semaphore main signal

On lines currently operated by the Hellenic Railways Organisation (OSE), signalling was not installed until World War II. There were few trains running and all traffic control was performed by the station masters (Greek: Σταθμάρχης). They controlled trains by hand signals and whistles and also delivered written orders to the train drivers for special operating procedures. Station managers were coordinated by morse-code landline telegraph and, later, by telephone.

The first semaphore signals were installed by the German military occupation forces during World War II and are almost identical to the "H/V" signalling system of the Deutsche Reichsbahn of the same period. Main signals consisted of two arm semaphores and distant signals of yellow disks. These signals controlled the entrance to stations and were operated mechanically by wire from the station platform. Usually on each direction there was one semaphore controlling the entrance to the station, preceded by a distant signal. Some of them still survive, but they are no longer operational.

Local signalling using two aspect colour light signals controlled by the station manager was installed at some busy stations like Athens/Larissis Station, Athens/Peloponnese station, Inoi junction etc.

All aspects of railways signalling are described in the current version of document "Γενικός Κανονισμός Κυκλοφορίας - Μέρος Α - Κανονισμός Σημάτων και Παραρτήματα I, II, III, IV, V & VI". This is a collection of different regulations, the main part covering semaphore signals and lineside signs, with appendices covering new signalling systems. It was issued in electronic format by Hellenic Railways Organisation in 2009.[1] The contents of this document include:

Semaphore signalling

Semaphore signals followed the German pattern and consisted only of home signals (German: Einfahrsignal) with the corresponding distant signals, covering the entrance to stations and are described in Chapter II of the Signalling Regulation. There were no starting semaphore signals (German: Ausfahrsignale), as the trains were signalled out by the Station Master in person, holding up a staff with a green disk and blowing his whistle. This practice was followed when colour light signals were first installed in the sections Athens - Inoi Junction and Thessaloniki - Platy, even though the new system included starting signals, but it was abandoned later, with the introduction of the current signalling system.

Signal OSE Code Meaning Next signal Notes
11b Stop - Stop immediately and wait outside the station
11d Proceed Entrance to station free, unless it is restricted by other signals.
11e Slow Proceed into station, entering a diverging line at a junction
or the secondary line of a passing loop.
20a Caution 11b Reduce speed to stop at the main signal.
20b Caution 11e Reduce speed to proceed with low speed after main signal.
20c Clear 11d Main signal is clear

Radio communications

Around 1973, as a result of a serious train accident that took place between Doxaras and Orfana stations in Thessaly, the Hellenic Railways Organisation installed VHF/FM radios on all stations and driving cabs. In many cases the orders are transmitted over the radio by station masters, instead of being handed out in printed form. In the past OSE used ten different VHF frequencies. An allocation of 150.05 to 151.6 is reserved for the VHF/FM service.[2] Today operations use four channels as follows:

Channel Frequency
(kHz)		 Mode Usage
1 150.290 Simplex Peloponnese network and Ormenio - Thessaloniki - Amyntaio - Florina - Kozani
2 150.310 Simplex Piraeus - Thessaloniki - Eidomeni mainline
3 150.330 Simplex Locomotive and train depots
4 150.350 Simplex Reserve

The suburban section from Acharnai Railway Center to the Athens International Airport station uses commercial TETRA radio instead of VHF/FM.

Currently the VHF/FM system is being phased out and replaced with a digital communications network based on the GSM-R technology which shall also carry ETCS-Level 1 cab signalling. The GSM-R system was designed by an engineering consortium (DeConsult-Lahmeyer-TRADEMCO) and is implemented by Siemens. Frequency bands 876-880 MHz and 921-925 MHz have been specifically reserved for the GSM-R/ETCS service.[3]

Modern signalling

A four aspect colour light signal at Lianokládi

In recent years the Hellenic Railways Organisation undertook modernisation of the section from Piraeus to Thessaloniki and Idomeni. This line is using block signalling with centralized control from a small number of signal boxes (Appendix III of Signalling Regulation). Signals are four aspect colour light signals, which are described in the following table. Of course some signals have only three or two aspects when there is no need for all possible indications (for example if the signals are not followed by points). There are even a few single aspect signals, displaying either steady of flashing amber (ΦΠ-10 and ΦΠ-12). Currently the colour light signalling is functional on the following sections:

On the following sections the installation of signalling is at an advanced stage:

Slightly different signalling systems were originally specified for the sections Athens - Inoi Junction and Platy - Thessaloniki, which are described in Appendix II of the Signalling Regulation.

Specialized local signalling systems exist at:

The following table describes the modern (Appendix III) signalling system.

Signal OSE Code Meaning Next signal Notes
ΦΠ 0 Stop –
ΦΠ 1 Proceed ΦΠ 1 Proceed with maximum speed for section, unless it is restricted by other signals.
ΦΠ 2 Slow ΦΠ 1 Proceed with a maximum speed of 40 km/h from the signal to the exit of points area.
Usually indicates that the train enters a diverging line at a junction or the secondary
line of a passing loop.
ΦΠ 10 Caution ΦΠ 0 Reduce speed to stop at the next signal.
ΦΠ 12 Caution ΦΠ 2
ΦΠ 20		 Reduce speed to proceed with low speed after next signal.
ΦΠ 20 Slow.
Stop at next signal		 ΦΠ 0 Proceed with a maximum speed of 40 km/h from the signal to the exit of points area.
Next colour light signal is red. Usually indicates that the train enters a passing loop
while the starting signal at the other end of the loop displays a red aspect.

Signals are tagged with an identity which consists of a three or four letter code denoting the station and a number (for example "OIN 3"). Distant signals share the same number with the corresponding main signal with the addition of letter "A" in front of the number (for example "OIN A3").

Switch points

A points operation lever and indicator (Signal 31)

Most switch points, especially those located in stations and marshaling yards, are equipped with a position indicator, (Signal 31) which is directly connected to the points operation mechanism. When the points are set to the through track, it displays an orange rectangle to the facing-point movements and a white rectangle to trailing-point movements. When the points are set to the diverging route, the indicator displays a diagonal arrow to the facing-point movements and a white circle to the trailing-point movements.

ISAP signalling

Operating console for signals and points used at Omónia station

Athens-Piraeus Railway, the predecessor of Athens-Piraeus Electric Railways, installed a signalling and points control system in 1900-1904, during the electrification of the line. The mechanical signalling system was designed by Siemens & Halske and used semaphores for the main signals and square boards for the distant signals. Most semaphores had one arm, whilst a small number, which were followed by points, had two arms.

The line between Piraeus and Omonoia Square was divided in six blocks. Details of the design and operation of the signals, the points and the interlocking survive in Section D of the contract between the Greek Government and the railway company.[4] The system became operational in 1904.[5]

In 1924 the new company "Hellenic Electric Railways" signed a new contract with Siemens & Halske to renovate the signalling system. The semaphores were replaced with colour light signals and electrical interlocking.[6] In the early 1950s colour light signalling was installed in the extension from Omonoia station to Kifissia station.

Most signals are "main signals" with two aspects (red and green). There are also a few two aspect (yellow and green) distant signals, in locations where the main signal is not visible from a reasonable distance. If the points at a junction are set to a diverging route, this is indicated by a special "junction signal", a white diagonal line on black background. Junction signals are usually colocated with main signals, although there are quite a few stand-alone ones.

Main signals and junction signals are tagged with a number identity. Distant signals are tagged with the same number as the corresponding main signal, preceded by "Vs" (German: Vorsignal).

A new modernization programme began in 1982, still using mainly two aspect colour light signals. Gradually the signalling system was adapted to central control from a power signal box next to Eirini station. The line circuits operate with audio frequency alternating current (Siemens FTGS 17). In 1983 ISAP installed an electomagnetic Indusi cab signalling system, which was supplemented after 2003 with an Automatic Train Protection (ATP) system.[7]

Signal ISAP Code Meaning Next signal Semaphore
equivalent		 Notes
STOP
PROCEED
CAUTION STOP Displayed by a small number of distant signals at locations with poor visibility.
PROCEED PROCEED When displayed by a distant signal.
Junction signal.
When illuminated indicates that points are set to a diverging route.

A VHF/FM simplex radio system was installed in stations and driving cabs in 1985, which operated on 161.325 and 161.375 MHz. It was replaced with a UHF/FM repeater operating on 418.575 MHz in 2004. This system was supplemented with a TETRA system in 2004. However radio is rarely used for train control under normal operating conditions.[8]

Athens Metro signalling

Signalling on the two lines of Athens Metro is centered on an Automatic Train Protection (ATP) system, type LZB 700, compatible with the ISAP ATP system. An Automatic Train Operation (ATO) system has also been installed and is under evaluation. In the short section between Larissa station and Sepolia Depot an Indusi system was installed initially, so that the section could be used by ISAP trains, however this was later removed.[9] The network is controlled by operators stationed in a central signal box located at Syntagma station.

Points are protected by two aspect color light signals, designated as "switch point indicators". Initially these signals display either a white or a red light. Recently the white aspect was replaced with a green aspect.

STOP GO

Signals are tagged with an identity which consists of a three letter code denoting the station and a number (for example "ΣΥΝ 11").

Initially stations and driving cabs were equipped with UHF/FM radios operating on 8 simplex channels between 418.6 and 418.775 MHz, which were replaced with TETRA radios in 2004.[10]

Athens Tram signalling

At level crossings Athens Tram uses special light signals which are coordinated with road traffic lights. The signals are quite different from regular rail signals, in order to avoid confusion with adjacent road traffic lights. At some locations green wave signalling has been established, giving priority to approaching trams over road vehicles.

STOP CAUTION GO

All Athens Tram driving cabs are equipped with GPS receivers and TETRA radio telephones.[11]

References

  1. ↑ "General Rail Traffic Regulation - Part A- Signals Regulation and Appendices I, II, III, IV, V & VI" (Greek: Γενικός Κανονισμός Κυκλοφορίας - Μέρος Α - Κανονισμός Σημάτων και Παραρτήματα I, II, III, IV, V & VI) , Hellenic Railways Organisation, electronic edition (2009).
  2. ↑ National Frequency Allocation Tables, Ministerial Decision 17225/655, 10 March 2006, Government Gazette Issue B'399/2006, page 4904.
  3. ↑ National Frequency Allocation Tables, Ministerial Decision 17225/655, 10 March 2006, Government Gazette Issue B'399/2006, pages 4911-4912.
  4. ↑ G. Nathenas; A. Kourbelis; T. Vlastos; S. Kourouzidis; V. Katsareas; P. Karamanis; A. Klonos; N. Kokkinos (2007). Από τα Παμφορεία στο Μετρό (in Greek). 2. Athens: Μίλητος (Militos). pp. 574–576. ISBN 978-960-8460-91-1.
  5. ↑ 130 Χρόνια Ηλεκτρικοί Σιδηρόδρομοι Αθηνών-Πειραιώς Α.Ε. (130 years of Athens-Piraeus electric railways). ISAP. 1999–2005. pp. 58, 63, 99–105. ISBN 960-86477-0-3.
  6. ↑ 130 Χρόνια Ηλεκτρικοί Σιδηρόδρομοι Αθηνών-Πειραιώς Α.Ε. (130 years of Athens-Piraeus electric railways). ISAP. 1999–2005. p. 59. ISBN 960-86477-0-3.
  7. ↑ G. Nathenas; A. Kourbelis; T. Vlastos; S. Kourouzidis; V. Katsareas; P. Karamanis; A. Klonos; N. Kokkinos (2007). Από τα Παμφορεία στο Μετρό (in Greek). 2. Athens: Μίλητος (Militos). p. 636. ISBN 978-960-8460-91-1.
  8. ↑ G. Nathenas; A. Kourbelis; T. Vlastos; S. Kourouzidis; V. Katsareas; P. Karamanis; A. Klonos; N. Kokkinos (2007). Από τα Παμφορεία στο Μετρό (in Greek). 2. Athens: Μίλητος (Militos). p. 637. ISBN 978-960-8460-91-1.
  9. ↑ G. Nathenas; A. Kourbelis; T. Vlastos; S. Kourouzidis; V. Katsareas; P. Karamanis; A. Klonos; N. Kokkinos (2007). Από τα Παμφορεία στο Μετρό (in Greek). 2. Athens: Μίλητος (Militos). p. 709. ISBN 978-960-8460-91-1.
  10. ↑ G. Nathenas; A. Kourbelis; T. Vlastos; S. Kourouzidis; V. Katsareas; P. Karamanis; A. Klonos; N. Kokkinos (2007). Από τα Παμφορεία στο Μετρό (in Greek). 2. Athens: Μίλητος (Militos). p. 710. ISBN 978-960-8460-91-1.
  11. ↑ Γ. Καλογιάννης (2006). Ηλεκτρονικά συστήματα τηλεματικής, ελέγχου και ασφαλείας Τράμ (PDF). Ηλεκτροκίνητα μέσα μεταφοράς στην Ελλάδα - Υφιστάμενη κατάσταση και προοπτικές (in Greek). Technical Chamber of Greece. Retrieved 2010-09-23.
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